Document ev6gLnoYYy2yDZBmGR27MJJJ9

272 CHAPTER 13 The Technical Advisory Committee on Weather Design Conditions has suggested that wet-bulb design temperature be taken as that wet-biilb temperature which has been equalled or exceeded in 5 percent of the horns during months of the period of record. While not available for the 1953 edition of The Guide, due to the tremendous task of compiling these data it is hoped that they will be available for some stations for future editions! The wind velocity to be used in design should be that wind velocity which accompanies the design temperatures in each instance, but since these data are not available, the average summer wind velocities for the period of record were taken from U. S. Weather Bureau records revised to 1948, It is pointed out that this is not necessarily the velocity which coincides with the design temperatures, but it may serve as a guide to the designer. Other weather data, such as daily range of temperature, are useful particu larly when making cooling load calculations for an early morning peak on an east exposure. Daily range of temperature,is the difference between the average of the daily maximum dry-bulb temperatures and the average of the daily minimum temperatures. This, range is highest in semi-arid or desert regions and at high elevations, and lowest near the oceans or very large lakes. The daily range of temperature (Fahrenheit degrees) in July for the principal areas of the United States can be approximated from the following tabulation: East Sea Shore............ 12 to 18 East of Mississippi River...........................19 to 24 Gulf Sea Shore............ 12 to 18 Mississippi River to Rocky Mountains__ 24 to 33 Great Lakes Shore.... 18 to 21 Rocky Mountain Area................................ 33to42 West Sea Shore........... 15 to 20 West Coastal States....................................20 to 36 Ventilation Rate The introduction of outside air is necessary for the ventilation of condi tioned spaces. Chapter 6 suggests minimum outdoor-air requirements for representative applications; but it is to be emphasized that minimum re quirements are not necessarily adequate requirements for all psychological attitudes and physiological responses. Where maximum economy in space and load are essential, as in submarines or other restricted spaces, as little as 1 cfm of outside air per person has been found to be sufficient provided that satisfactory ventilation is simultaneously obtained by an adequate decontamination of recirculated air.2 Local codes and ordinances frequently specify ventilation requirements for public places and for industrial installations. For operating rooms> minimum requirements for safe practice are given in a National Board of Fire Underwriters' pamphlet.3 This pamphlet does not require 100 percent outside air in operating rooms, although 100 percent outside air is normally used and recommended. Recommended and minimum ventilation rates for the most common applications are summarized in Table 3. For further general applications, a basis of estimating the cfm per person may be taken as: 1. People not smoking...................................:. 7} Recommended 5 Minimum 2. People smoking..............................................40 Recommended 25 Minimum The cooling load due to the introduction of outside air for ventilation is determined once the indoor and outdoor design conditions are fixed. Cal culations will be discussed subsequently. Cooling Load 273 Table 2. Summer Climatic Conditions* Suggested Design Wet-Bulb and Dry-Bulb Temperatures Col. 1 State Col. 2 Station0 Col. 3 TION0 Ft Col. 4 OF RECORD* Col. 5 Highest Col. 6 Design Ever Recorded0 Temp, on T.A.C. 2k% Basis' F PF Col. 7 Design Temp, in Common Us * F Col. 8 Design Temp, in Common U8Ef F Summer Wind Velocity* Mph Ala...... Anninston. ... CO Birmingham.. ..CO Birmingham.. ..AP Mobile.......... ..CO Mobile.......... AP Montgomery.. . CO Montgomery.. ..AP Aril.... Flagstaff CO Kingman __ AP Phoenix....... CO TPWWuhiicnnossseollnooniwwx............................ AP AP CO AP Yuma........... CO Ark..... Fort Smith... CO Calif.... BBFLLaiiouttkttrrlltbeeeaSrsRRnmfikooe.ilcct.dh.kk_........... EFFDrruaeergssegnnkooea..t.t........................... ..AP CO ..AP AP .AP .AP CO CO AP OLRoeasdkAlaBnnlgudef.fl.e...s........ RReedddBinlugf.f......... SSSSaaaannccrrDDaammiieeeeggnnoott..oo............ .CO AP CO AP AP CO AP CO .AP Colo.. San San JForasen.c.i.s.c.o.. WDeilnliavmers........... ..CO CO AP CO Denver,... Durango...... .AP CO Conn.... PDPHNHuueraaaeewrrnbtbtffdHlloooorr.aJ.dd..uv.....n.e......cn...t.i.on...CCCACAOOOOPP d. c.... NWeawshHinagvtoenn...r.. AP CO n... Washington Apalachicola AP CO Jacksonville CO Jacksonville... AP Hey West... Key West...... Miami Miami... CO AP CO AP Pensacola..... .CO Pensacola . .AP iamp............. CO tampa....... AP 3... i ttusville .. Atlanta AP .AP Augusta........ Augusta.. . Macon......... Macon .CO AP .CO 'dahc. Savannah....... Savannah . Boise .CO AP Boise Burlev Idaho Falls__ AP Lewiston.. Pocatello ii.... Pocatello.. Cairo .CO CO AP Si'aaeo.......... fMcho|l?inaego.......... 733 1893-1947 711 1893-1945 615 1939-1947 143 1872-1947 219 1940-1947 293 1872-1947 226 1938-1944d 6957 1899-1947 3473 1935-1939 1122 1895-1947 1112 . 1933-1947 2561 1935-1939 4853 Up to 1946 4899 1937-1947 146 1876-1946 545 1882-1945 463 1945-1947 451 1879-1942d 282 1942-1947 499 1937-1946 740 1931-1947d 1925 1935-1939 132 1886-1947 387 1887-1939 281 1939-1947 534 1877-1947 21 1929-1947 305c 1877-1934 346- 1944-1947 579 1935-1939 116 1877-1947 22: 1938-1947 90 - 1871-1940 34 1939-1947 164 1875-1947 100 Up to 1946 124 1935-1939 5398 1871-1947 5379 1934-1947 6558 Up to 1946 4587c Up to 1946 4770 1889-1938 4810 1939-1947 229 1905-1940d 20 1940-1947 180 1872-1947 17 1943-1947 128 1871-1947 20 1935-1939 23 1922-1947 104 1871-1947 29 1938-1947 23 1871-1947 48 1939-1947 253 1896-1947 13 1940-1947 67 1879-1947 113 1943-1947 111 1890-1940 12 1941-1946" 52 1935-1939 1020 1935-1939 195 1871-1946 424 1939-1947 408 1899-1947 432 1939-1947 115 1871-1945d 56 1939-1947 2818 1864-1939 2849 1939-1947 4150 1935-1939 4744 1935-1939 763 1900-1944d 4522 1899-1947 4467 1938-1947 319 1872-1947 601 Up to 1946 615 1935-1939 594 1932-1647 105 107 103 103 104 107 103 93 107 118 117 112 107 103 120 113 107 110 107 113 111 113 85 . 115 111 109 102 115 112 112' 114 108 110 106 101 106 116 105 104 99 105 104 104 101 98 101 94 106 106 102 104 105 100 95 96 100 103 105 98 98 98 102 106 105 105 1 . 102 105 105 109 104 100 117 105 103 106 105 107 94 92 99 io7 102 95 97 104 94 104 . i03 80 ioi 79 103 93 95 88 84 92 94 89 90 93 93 95 94 88 '92 92 M . 95 78 95 78 5.4 95 80 8.6 95 78/ 90 65 105 76 6.0 105 72 100 70 iio 78 95 76 6.i 95 .78 6.2 ios : 76 ... 90 65 105 74. 7.9 90 70 5.8 ' 85 65 100 70 ioo 85 85 91 95 95 95 95 93 , 95 95 95 95 98 9i 95 95 72 68 65 70 64 65 65 65 `.. 75 - 75 ' ;78 - 80 78 . ' 78 . 79 78 ' 78 7.9 10.7 6.9 6.3 7.45.9 8.4 8.7 7.4 95 . 98 95 95 m ' 76 76 78 . 78 00 7.9 8.0 95 65 95 65 98 78 95 75 9-5